Self-Assembly and Chaining of Particles in Viscoelastic Liquids: Fundamentals and Applications

粘弹性液体中颗粒的自组装和链接：基础知识和应用

• 批准号: 0828104
• 负责人: Roger Rangel
• 金额: $ 30万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0828104&HistoricalAwards=false
• 关键词: Self; Assembly; Chaining; Particles; Viscoelastic

CBET-0828104RangelIntelectual Merit: The proposed work seeks our understanding and establishes applications of the properties of aggregation, self-assembly and chaining of small particles in flows of polymer solutions (viscoelastic fluids). Particle-particle interactions in viscoelastic fluids are dramatically different than in Newtonian fluids: particles disperse in the flow of Newtonian fluids and they aggregate in the flow of viscolastic fluids. We have done analyses which suggest that the chaining of the particles in viscoelastic liquids is local and based on two pillars; the first is a viscoelastic ?pressure? generated by normal stresses due to shear. The second is due to the change in the sign of the normal stress which we compute in the second-order order fluid. Different numerical and experimental experiments will be carried out to validate this theory. We will establish the limits of particle size, concentration, particle to fluid density ratio, liquid rheological parameters, flow field etc for which particles aggregate in viscoelastic fluids. The basic assumption of particle image velocimetry (PIV) is that small particles seeded in fluid will not interact in flow. This assumption is valid for Newtonian fluids where tracer particles disperse, but it will not work in viscoelastic fluids in situations in which particles aggregate. This study will determine the conditions under which small particles track the flow, as is assumed in studies of PIV. Understanding the rage of parameters at which interaction and chaining of particles occurs will benefit several other applications in oil, composite, food, and pharmaceutical industries.Broader Impacts: The participation of women and individuals of underrepresented groups in the proposed effort will be encouraged by coordinating recruitment of new graduate students through established programs at UC Irvine. These student oriented programs are designed to encourage the participation of women and minorities in the science and engineering fields and include the Center for Opportunities and Diversity in Engineering (CODE) and the California NSF Louis Stokes Alliance for Minority Participation (CAMP). One of the coPIs is the UCI Division Director for CAMP and he will provide a connection between this project and the underrepresented STEM students on campus interested in research. The research team includes two female graduate students. In 2005, female graduate students comprised 150 out of a total number of 630 graduate students enrolled in the Henry Samueli School of Engineering at UCI, representing 24% of the student body. The graduate level research opportunities generated by this effort will be used to support these underrepresented graduate students in engineering and provide a solid base for advancement to the postdoctoral level and future achievement in academia. The project will also provide research opportunities for undergraduate students through the Undergraduate Research Opportunities Program (UROP) at UCI. The investigators have a long history of involvement in this program and will ensure the participation of undergraduates, particularly in the experimental aspects of the project.

智力优势：本研究旨在理解并建立聚合物溶液（粘弹性流体）中小颗粒聚集、自组装和链化特性的应用。粘弹性流体中的粒子-粒子相互作用与牛顿流体中的粒子相互作用有很大不同：粒子在牛顿流体中分散，而在粘弹性流体中聚集。我们已经做了分析，表明粘弹性液体中的颗粒链是局部的，基于两个支柱；第一个是粘弹性压力？由于剪切而产生的正应力。第二个是由于我们在二阶流体中计算的正应力符号的变化。将进行不同的数值和实验实验来验证这一理论。我们将建立颗粒在粘弹性流体中聚集的粒径、浓度、颗粒与流体密度比、液体流变参数、流场等限制。粒子图像测速（PIV）的基本假设是，在流体中播撒的小颗粒在流动中不会相互作用。这一假设适用于示踪颗粒分散的牛顿流体，但不适用于颗粒聚集的粘弹性流体。这项研究将确定小颗粒跟踪流动的条件，就像在PIV研究中假设的那样。了解相互作用和颗粒链发生的参数范围将有利于石油、复合材料、食品和制药行业的其他应用。更广泛的影响：通过加州大学欧文分校的现有项目协调新研究生的招聘，将鼓励妇女和代表性不足群体的个人参与拟议的努力。这些以学生为导向的项目旨在鼓励女性和少数民族参与科学和工程领域，包括工程机会和多样性中心（CODE）和加州国家科学基金会路易斯斯托克斯少数民族参与联盟（CAMP）。其中一名copi是UCI CAMP的部门主任，他将在该项目与校园中对研究感兴趣的未被充分代表的STEM学生之间建立联系。研究小组包括两名女研究生。2005年，在UCI Henry Samueli工程学院注册的630名研究生中，女研究生占150名，占学生总数的24%。这项工作所产生的研究生水平的研究机会将用于支持这些代表性不足的工程研究生，并为进入博士后水平和未来在学术界取得成就提供坚实的基础。该项目还将通过UCI的本科生研究机会计划（UROP）为本科生提供研究机会。研究人员在这个项目中有着悠久的参与历史，并将确保本科生的参与，特别是在项目的实验方面。